During operation the wheels of railroad rolling stock (such as locomotives and railroad cars) become worn. This wear often increases the risk of train derailment and, additionally, may accelerate wheel .wear or otherwise adversely affect the running characteristics of the wheels.
These wheels of railroad rolling stock may, with wear, develop flat areas on their circumferences. Such wear often causes a bumpy or vibratory rotation of the worn wheel against the rail. Additionally, such worn wheels may cause derailment of the railway vehicle.
It is thus critical to maintain railway wheelsets to attempt to avoid this condition and, where it occurs, to grind or machine the wheel's circumference so that it is once more perfectly round and concentric with the axial centerline of the wheel and the wheelset. Wheelset truing machines are often used to accomplish this end. These machines are well known to those skilled in the art and are described, e.g., in U.S. Pat. Nos. 4,825,737, 4,680,846, 4,276,793, 4,265,149, 4,200,012, 4,134,314, and the like. The disclosure of each of these United States patents is hereby incorporated by reference into this specification.
Most wheelset truing machines require that the wheelset be located in a centered position with respect to the machining device so that accurate concentricity between the wheel circumference and the axial centerline will be obtained. Additionally, once the machining operation has been completed, the wheelset must be located in a centered position in order to measure the accuracy of the machining.
Axle bearing boxes (bushings through which the axle passes in the hub of a wheel) are commonly located on both ends of the railway wheelset. See, e.g., U.S. Pat. Nos. 5,358,072, 5,237,933, 5,235,.918, 5,213,049, 5,189,962, 4,527,487, 3,588,204, 3,531,166, and the like; the disclosure of each of these patents is hereby incorporated by reference into this specification.
One could remove these axle bearing boxes to locate the wheelset's true center; the axle of the wheelset, which runs true with the wheelset axial centerline, could then be used to locate the true center of the wheelset with a simple double roller centering device.
However, it is generally not desirable to remove the axle bearing boxes, even during truing operations, because of the possibility of contamination of the bearings and grease packed therebetween. Consequently, a measuring device which would allow the location of the wheelset's true center without requiring the removal of axle bearing boxes would be desirable.
It is an object of this invention to provide a measuring device adapted to locate a wheelset's true center without requiring the removal of axle bearing boxes.